With development of communications networks, a service interface gradually changes from a time division multiplexing (TDM, Time Division Multiplexing) interface to a packet interface. For a microwave network, a service that a microwave link bears also changes accordingly. A packet service and a TDM service have different features; therefore, different mapping methods are used when a packet of the packet service is multiplexed to a microwave frame.
A common method for mapping a packet to a microwave multiplexing frame is a generic framing procedure (GFP, Generic Framing Procedure) mapping method. In the GFP mapping method, a sending node may perform GFP encapsulation on each received packet, adds a GFP overhead, and thereby form multiple GFP data units. Then, the multiple formed GFP data units are put into a microwave multiplexing frame and transmitted to a destination node of the packet.
However, when the GFP encapsulation is performed on a packet, a GFP overhead of at least eight bytes needs to be added to each packet. A packet actually transmitted over the network, however, generally have small packet length, for example, a voice packet and a Transmission Control Protocol (TCP, Transmission Control Protocol) response packet. When a GFP overhead of eight bytes is added to each packet, the GFP overhead accounts for a large data volume proportion in a GFP data unit that is obtained after the encapsulation, that is, the GFP overhead occupies a lot of link transmission bandwidths, which reduces bandwidth usage of a transmission link.